Control apparatus



im! im' IN VEN TOR.

WAYNE H. SCHUTMAAT ATTORNEY United States Patent O 3,173,245 CNTROL APPARATUS Wayne H. Schutmaat, Needham, Mass., assignor to Standard-Thomson Corporation, Waltham, Mass., a corporation of Delaware l Filed Mar. 4, 1963, Ser. No. 262,724 13 Claims. (Cl. 61E- 23) This invention relates to controlV apparatus. The invention relates more particularly to control apparatus which is capable of locking or retaining a movable element in a given position.

An object of this invention is to provide apparatus which is capable of locking a movable element in a given position.

Another object of this invention is to provide such apparatus which is thermally operated.

Another object of this invention is to provide such apparatus in which electrical means may be employed tofcontrol the thermal energy.

Another object of this invention is to provide such apparatus which is capable of producing high values of force in consideration of the physical size thereof.

Another object of this Ainvention is to provide such apparatus in which the rate of operation therof may be controlled.

Other objects and advantages reside in the construction of parts, the combination thereof, the method of manufacture, and the mode of operation, as will become more apparent from the following description.

In the drawings:

FIGURE 1 is a sectional diagrammatic view of apparatus of this invention showing elements of the apparatus in deactuated positions.

FIGURE 2 is a sectional diagrammatic view of the apparatus of FIGURE l showing elements of the apparatus in actuated positions.

FIGURE 3 is a diagrammatic view showing apparatus of this invention and control mechanism therefor in combination with a fluid valve.

FIGURE 4 is a diagrammatic sectional view of a modication of a portion of the apparatus of this invention.

FIGURE 5 is a diagrammatic sectional view of another modification of apparatus of this invention.

Referring to the drawings in detail, apparatus of this invention shown in FIGURES l and 2 comprises a rigid container 10. A rod or shaft 12 extends through the container and is normally reciprocally axially movable with respect to the container 10.

Within the container 10 and encompassing the rod 12 is a quantity of thermally responsive expansible-contractible material 14. The material 14 may be any material which has a suitable expansion characteristic over a desired temperature range. Hovever, preferably, the material 14 is a material which remains substantially solid at all operating temperatuures thereof so that sealing means between the rod 12 and the container 10 may vnot be required. For such use polyethylene, polypropylene, nylon or the like has been found to be satisfactory. In the use of some solid materials within this invention, container means therefor may not be required. However, the material 1 4 within the container 10 may be a material which becomes a liquid when heated within the operating range of the apparatus if proper sealing means are used between the container 1G and the rod 12.

A heater element 16 is in thermal exchange relationship with the material 14. Herein the heater element 16 is an electric heater coil which encompasses the container 10 and is adapted to heat the container 16, which, in turn, heats the material 14.

A connection lead 18 joins a portion of the heater rice 2 element 16 to va switch 2i). A terminal lead 22 is also joined Vto the switch 2t). A conductor 24 is connected to an opposite portion of the heater element 16. The conductors 22 and 24 connect to a source of electrical energy.

The material 14 under normal temperature conditions exerts no appreciable pressure upon the rod 12. In fact, under normal temperature conditions the material 14 may not completely till the container 10, as shown in FIGURE 1. Therefore, as stated above, the rod 12 is normally freely axially movable with respect to the container 10. However, when the switch 20 is closed, as shown in FIGURE 2, the heater element 15 is energized and the thermally responsive material 14 within the container 1i) is heated and expands in volume. After a given period of time, the material 14 completely lls the container 1li and applies substantial pressure upon the rod 12, as well as upon the walls of the container 10. Such pressure of the material 14 locks or secures the rod 12v with respect to the container 10.

Any suitable electrical control means for energization of the heater element 16 may be employed to prevent overheating of the material 14, thus preventing the occurrence of excessive pressures of the material 14 within the container 10. The rod 12 may be attached to any desired suitable element or mechanism for operation therewith.

Therefore, it is understood that control apparatus of this invention comprises means by which thermal energy may be used to control the operation of forces which lock an element 0r mechanism against operation. The thermal energy may be controlled and provided electrically or by any other suitable means.

When it is desired to release the rod 12, the heater element 16 is deenergized, permitting the material 14 to cool so that the material 14 contracts in volume and releases the rod 12 for axial movement thereof with respect to the container 10.

FIGURE 3 FIGURE 3 illustrates apparatus of this invention in combination with a uid valve 29. The valve 29l is providedk with a housing 30 which has internal portions 32 and 34 forming a valve seat 33. A closure member 35 is normally in engagement with the valve seat 33 to close the valve 29. The closure member 35 is urged toward the valve seat 33 by a spring 36. The spring 36 is compressed between the closure member 35 and a Wall 37 of the housing 30. A stem 38 is atttached to the closure memler 35 and extends through the wall 37 ofthe housing 3 The stem 38 also extends through a container 40 which is disposed adjacent the housing 30 and has thermally responsive expansible-contractible material 42 therein. An electric heater element 45':l is in thermal exchange relationship with the material 42 within the container 40.

A container 44 is adjacent the `container 40 and may be integral therewith orfattached thereto, if desired. The stern 3S extends through the container 44? However, within the container 44 the stem has a tapered portion 46 which is joined to a larger diameter portion 50. Within the container 44 and lencompassing the stem 3S is a quantity of thermally responsive expansible-contractible material 52. An electric heater element 54 is in thermal exchange relationship with the material 52. The stem 38 terminates adjacent the container 44.

A normally closed limit switch v56 is positioned adjacent the end ofthe stern 38 and is operable to open position by the stem 3S after a given amount of axial movement thereof.

The uid valve 29 is shown herein as being a part of an automatically controlled heating system. Fluid iowingthrough the valve 29 heats the space in which a thermostatic switch 60 is located. The thermostatic switch 60 is shown connected by means of a conductor 64 to one end of a transformer winding 62. The thermostatic switch 60 has a heat position H and a cool position C.

The heat position H of the thermostatic switch 60 is joned to the limit switch 56 by means of a conductor 66. A conductor 68 connects the switch 56 to one end of the heater element 54. The other end of the heater element 54 is connected to the opposite end of the transformer winding 62 by means of a conductor 70.

A conductor 72 joins the heat position H of the thermostatic switch 60 to one end of the heater element 43. The other end of the heater element 43 is connected to the opposite end of the transformer winding 62 by means of a conductor 76.

Normally the thermostatic switch 60 is in its cool position C, as illustrated by a solid line. However, if the temperature of the air in Contact with the thermostatic switch 60 ybecomes lower than a given predetermined value, the thermostatic switch 60 moves to its heat position H, as shown by a broken line. When the thermostatic switch 60 is in its heat position H, the heater element 54 and the heater element 43 are energized.

Thus, the thermally responsive material 52 within the container 44 is heated and the thermally responsive material 42 within the container 40 is heated. Therefore, there is expansion of the material 42 Within the container 40 and there is expansion of the material 52 within the container 44. Expansion of the material 52 causes a pressure to be applied upon the tapered portion 46 of the stem 38. This pressure causes axial movement of the stern 38 in a direction toward the limit switch 56. Such movement of the stern 38 moves the closure member 35 from the valve seat 33 of the fluid valve 29. Such movement of the stem 38 is against the forces of the spring 36 which engages the closure member 35. When such movement of the closure member 35 occurs in a direction from the valve seat 33, uid is permitted to ow through the valve housing 30.

When the stem 38 moves to such an extent that the stem 38 engages the limit switch 56 causing opening thereof, the circuit to the heater element 54 is opened. Thus, the thermally responsive material 52 within the container 44 is permitted to cool and to contract in volume.

However, due to the fact that the heater element 43 is energized simultaneously with energization of the heater element 54, the thermally responsive material 42 within the container 40 is also heated and expands during expansion of the material 52 within the container 44. The expansion characteristics and quantity of the material 42 within the container 40 are so determined and energization of the heater element 43 is so governed that expansion of the material 42 applies a locking force upon the stem 38 at substantially the same time that the stern 38 moves into engagement with the limit switch 56, causing opening thereof.

Thus, as the stem 38 reaches the limit of its travel, the stem 38 is locked in position by the expanded condition of the material 42 the container 40. Therefore, the closure member 35 is retained in a maximum spaced position from the valve seat 33 and the Huid Valve 29 is in its maximum open position for flow of uid therethrough.

As stated above, ow of iiuid through the fluid valve 29 causes heating of the air which contacts the thermostatic switch 60. Therefore, after the valve 29 has been in an open condition for a period of time, the thermostatic switch 60 is heated to such a degree that the switch 60 operates to its cool position C. When such operation of the switch 60 occurs, the electrical circuit to the heater element 43 is opened.

Thus, the material 42 is permitted to cool and to contract in volume. Such contraction of the material 42 releases the stem 38 and permits the spring 36 to move the closure member 35 into engagement with the valve seat 33. The fluid valve 29 is thus again closed so that no uid flows therethrough.

Thus, it is understood that in the apparatus of FIG- URE 3 electrical energy is applied for only a limited period of time for opening -of the iiuid valve 29 and a reduced amount of electrical energy is required to retain the uid valve 29 in open position. Therefore, the apparatus as shown in FIGURE 3 provides means by which a fluid heating system is accurately electrically controlled.

FIGURE 4 FIGURE 4 shows a modication of apparatus of this invention. A container has thermally responsive material 82 therein. A heater element 84 is also within the container 80 and is in heat exchange relationship with the material 82. A rod or shaft 86 extends through the container 80 and is normally movable with respect to the container S0, as discussed above with respect to the rod 12 of FIGURES l and 2. The rod 86 is provided with a plurality of grooves or notches 88. Therefore, upon expansion of the material 82 within the container 80, pressure of the material 82 within the grooves or notches 88 and within the container 80 provides a very high degree of locking force to retain the position of the rod 86 with respect to the container 80.

FIGURE 5 In FIGURE 5 a container 90 has a quantity of thermally expansive material 82 therein. A rotatable shaft 94 has a plurality of elongate axially extending grooves 96 within the container 90. A heater element 98 is in heat exchange relationship with the material 92.

During normal conditions the shaft 94 is readily rotatable. However, when the material 92 is heated and a given amount of expansion occurs, pressure of the material 92 within the container 90 and within the grooves 96 locks the shaft 94 against rotation with respect to the container 90. Such apparatus is employed in brake or clutch mechanism or is adapted for use in other types of mechanisms.

Although the preferred embodiment of the device has been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, as disclosed and defined in the appended claims.

The invention having thus been described, the following is claimed:

l. Locking apparatus for a shaft comprising:

a rigid container,

the shaft extending into the container and normally movable with respect thereto,

a quantity of thermally responsive expansible-contractible material within the container encompassing the shaft and operable by expansion to completely fill all available space within the container and to apply pressure upon the shaft to retain the position of the shaft against movement thereof with respect to the container,

heater means in thermal exchange relationship with the thermally responsive material for causing heating and expansion thereof so that upon sufficient energization of the heater means the material expands and iills all available space within the container and the pressure of the thermally responsive material within the container and upon the shaft secures the shaft against movement with respect to the container.

2. The apparatus of claim l in which the heater means is electrical.

3. Locking apparatus comprising:

a container,

a shaft having a portion Within the container and a portion extending from the container, the shaft being a quantity of thermally responsive material within the container,

a rotary shaft having a portion Within the container and engageable by the material, the portionofthe shaft normally movable With respect to the container, 5 Within the container having axial grooves, the shaft a quantity of thermally responsive expansible-conbeingnormally rotatable with respectA to the contractible material within the container and operable tainer,

by volumetric expansion to apply pressure upon the and means for heating the thermally responsive mashaft, terial for expansion thereof, expansion of the mateheater means -in thermal exchange relationship With rial causing the material to lill all available space the thermally responsive material for heating therewithin the container so that the material applies presor", sure upon the portion of the shaft within the conthe heater means causing heating of the thermally retainer, securing the shaft against rotation with responsive material causing expansion thereof so that speer t0 l[he container,

the thermally responsive material fills all available 9. The mechanism of claim 8 in which the means for space within the container and applies pressure Withheating the thermally responsive material is electrical.

in the container and locks the shaft against move- 10, Apparatus of the 0f the type described Comprising;

ment With respect to the container. a container means,

4. The apparatus of claim 3 in which the heater means a shaft having a portion within the container means, a is electrical. portion of the shaft within the container means hav- 5. Locking apparatus comprising: ing a shoulder portion,

a container, thermally responsive expansible-contractible material an axially movable shaft extending through the conwithin the Container means,

rainer, heater means in thermal exchange relationship with the a quantity of thermally responsive expansible-conlthermally responsive material,

tractible material Within the Container and operable control means energizing the heater means, the control hy eXPanSion to lill all available Space Within the means including means energizing the heater means Container and aPPly ProSSlire Within the Container causing expansion of the material thus applying and uPon the Shaft, Siloh PreSSnro Securing the Shaft forces upon the shoulder portion of the stem causing against movement With reSPeCt t0 the Containor- 30 movement thereof with respect to the container 6. Locking apparatus comprising: means, the control means also including means enera rigid container, gizing the heater means causing expansion of the a rotary Shaft having a Portion Within the COrltailer thermally responsive material thus applying presand a Portion oXtendinS froIn the Container, sure upon the shaft to prevent movement thereof a quantity 0f thermally responsive expansibie-Con- 35 with respect to the container means.

tl'aCtble material Within the Container and BXpaIl- 11 Apparatus 0f the type desgfibed comprising:

sible in volume to apply greatly increased pressure a rigid Container,

Within the Container and Upon the Shaft So that the a member having a portion Within the container, the Shaft iS looked againSt i'otai'y movement With To member and the container being normally freely relspect to the container. 40 atively movable,

7. Control mechanism for valve apparatus having a a quantity of thermally responsive expansible-contractrooiProoally movable oloSUro member and a Stern at' ible material within the container, the thermally retached to the closure member for movement thereof, spensive material normally having a contrae/[ed yol comprising: umetic condition which permits free relative movefirst stationary container means encompassing the stem ment between the member and the container, the

and Provided With thermally reSPonSiVe oXPanSiblo' thermally responsive material being expansible in contractible material therein engageable vwith the volume by heat applied thereto so that the thermally stem, responsive material fills the available space within electric heater means in thermal exchange relationthe corr/rainer and applies pressure ro all internal por. ship with the thermally responsive material in the tions of the container and to the member, so that the nrst stationary container means, member and the container are not freely relatively second stationary container means encompassing the mavable,

stem and provided with thermally responsive expan- 12, Apparatus of the type described comprising: sible-contractible material therein engageable with arigid Container, the Stern, the Stom having a Sboulder Portion Within a member having a portion Within the container, the the second container means, member and the container being normally freely relelectric heater means in thermal exchange relationship atively movable,

with the thermally responsive material in the second pressure material within the container, the pressure container means, material normally having a contracted volumetric electrical control means connected to the electric heater condition which permits free movement between the means and to a source of electrical energy, the elecmember and Lhe container, the pressure material betrical control means including means energizing both ing expansible in volume 4so that the pressure mateof said electric heater means, means deenergizing the rial fills the available space Within the container and second said electric heater means while continuing applies pressure to all internal portions of the conenergization of the rst said electric heater means, tainer and to the member so that the member and the said second heater means causing expansion of the container are restrained against relative movement.

material within the second container means, thus 13. Apparatus of the type described comprising: causing pressure upon the shoulder portion of the arigid container, stem so that there is movement of the stem, the first a rotary member having a portion Within the container, said heater means causing expansion of the material thermally responsive expansible-contractible material Within the container, the thermally responsive expansible-contractible material being normally contracted in -volume Within the container so that a negligible pressure exists within the container and upon the shaft so that the member is normally freely rotatable with respect to they container, the thermally responsive material being expansible in volume as heat is applied thereto to apply greatly increased pressure of the material Within the container and upon the member so that the member is restrained against rotary movement with respect to the container.

References Citediu the le of this patent UNITED STATES PATENTS Timson Feb. 14, Kane Apr. 4, Lees July 24, Paschke July 23, 

5. LOCKING APPARATUS COMPRISING: A CONTAINER, AN AXIALLY MOVABLE SHAFT EXTENDING THROUGH THE CONTAINER, A QUANTITY OF THERMALLY RESPONSIVE EXPANSIBLE-CONTRACTIBLE MATERIAL WITHIN THE CONTAINER AND OPERABLE BY EXPANSION TO FILL ALL AVAILABLE SPACE WITHIN THE CONTAINER AND APPLY PRESSURE WITHIN THE CONTAINER AND UPON THE SHAFT, SUCH PRESSURE SECURING THE SHAFT AGAINST MOVEMENT WITH RESPECT TO THE CONTAINER. 